Need a reliable React Native developer to build your MVP or scale your mobile application? I help startups and businesses build fast, scalable, and production-ready mobile applications using React Native, Swift, and Kotlin. From MVPs to enterprise solutions, I focus on clean architecture, intuitive user experiences, and long-term maintainability. With 5+ years of professional experience, I've delivered mobile products for clients in the USA and UK across POS systems, workforce management, surveillance platforms, real estate, and marketplace applications. What I Can Help With ✔ React Native & Expo Development ✔ Cross-Platform Mobile App Development ✔ Native iOS (Swift) & Android (Kotlin) Development ✔ MVP Development for Startups ✔ Firebase, REST API & GraphQL Integration ✔ Authentication & Payment Gateway Integration ✔ Push Notifications & Real-Time Features ✔ Google Maps & Location Services ✔ Performance Optimization & Bug Fixes ✔ App Store & Google Play Deployment Tech Stack React Native • Expo • TypeScript • Swift • Kotlin • Jetpack Compose • Firebase • REST APIs • GraphQL • Git Why Clients Work With Me ✔ Production-ready, scalable code ✔ Clean and maintainable architecture ✔ Clear communication and fast response ✔ Business-focused solutions that deliver real value ✔ Reliable long-term support If you're looking for a developer who can turn your idea into a polished mobile product or improve an existing application, I'd be happy to discuss your project.

I bring 11+ years of experience in Mobile and Web Development, specializing in backend PHP/Laravel systems and native mobile apps using Kotlin, Swift, Objective-C, and Java. I build scalable, secure, and high-performance solutions tailored to your business needs. Our Agency Since 2016, my dedicated team and I have delivered top-quality digital solutions worldwide. ✔️ 150+ apps and platforms launched in the last year ✔️ $500K+ earned on Upwork ✔️ 122+ projects completed, 9,500+ hours logged ✔️ Nearly 100% client satisfaction ✔️ Experience working with startups and 7-9 figure enterprises My Expertise Backend & Web Development • PHP (Laravel, Symfony), MySQL, PostgreSQL, REST APIs, OAuth2, JWT Mobile App Development • Native Android (Java, Kotlin), iOS (Swift, Objective-C) • Cross-platform and API integrations Cloud & DevOps • AWS, Docker, CI/CD pipelines, scalable infrastructure Security & Authentication • Secure user authentication, SSO, role-based access control Why Work With Us? ✅ Custom solutions aligned to your goals and budget ✅ Agile development with clear milestones and communication ✅ Robust, well-tested, and maintainable code ✅ Competitive pricing with no surprises ✅ Proven success across fintech, eCommerce, logistics, and more Industries Served Finance, HealthTech, Logistics, E-commerce, SaaS, Real Estate, and more. What Clients Say "Fast, reliable, and communicative — delivered exactly what we needed on time." – Alexey Levashev, ZOOM International 𝗪𝗼𝘂𝗹𝗱 𝘆𝗼𝘂 𝗯𝗲 𝗮𝘃𝗮𝗶𝗹𝗮𝗯𝗹𝗲 𝗳𝗼𝗿 𝗮 𝟑𝟎-𝟔𝟎 𝗺𝗶𝗻𝘂𝘁𝗲 𝗳𝗿𝗲𝗲 𝗰𝗼𝗻𝘀𝘂𝗹𝘁𝗮𝘁𝗶𝗼𝗻? During this meeting, we will: ✔️ Discuss your project goals, challenges, and priorities ✔️ Outline a clear roadmap and cost estimate ✔️ Identify the best tech approach for your vision Send me a message to schedule your session. Looking forward to building something great together! Best regards, Stas

Need a Mobile App that actually scales, performs, and feels right to users? You’re in the right place. I’m a senior mobile developer with 8+ years of experience building 60+ production apps across fintech, e-commerce, healthcare, logistics, and on-demand platforms. I work primarily in Flutter and Kotlin, crafting clean, maintainable architectures and smooth user experiences that hold up in real-world usage. Here’s what I bring to your project: • Scalable mobile architecture (MVVM, Clean Architecture) • High-performance Flutter & native Android (Kotlin) apps • REST/GraphQL API integration & complex data flows • Real-time features (WebSockets, Firebase, push notifications) • Payment, maps, location, and 3rd-party SDK integrations • CI/CD, automated builds, Play Store/App Store releases • Leading remote teams & owning delivery end-to-end I don’t just code features — I help shape reliable mobile products. If you want someone who can translate ideas into polished, shipped apps (without hand-holding), let’s talk.

Building a ride hailing or delivery app is much more than putting a map on the screen. Real-time driver tracking, live trip updates, dispatching, payments, push notifications, chat, location accuracy, offline handling, and scaling to thousands of concurrent users all have to work together seamlessly. That's what I specialize in. I build production-ready ride hailing, taxi booking, delivery, courier, logistics, and mobility apps for iOS and Android using Kotlin Multiplatform, allowing you to launch both platforms without maintaining two separate codebases. I've spent 5+ years building mobile products used by millions of users, including real-time location systems, VoIP, AI-powered features, delivery platforms, and high-scale consumer applications. Building apps for iOS and Android doesn't have to mean two budgets, two timelines, and twice as many things that can break. I specialize in Kotlin Multiplatform and Compose Multiplatform, writing your app's logic once and sharing as much or as little UI as your product needs, while both platforms stay fully native where it matters. Your iOS users get a real iOS app. Your Android users get a real Android app. One codebase, both platforms, features shipping simultaneously. When your product needs AI, I can integrate it seamlessly into your mobile app. Whether it's an in-app assistant, document processing, semantic search, or on-device inference, I build solutions that balance performance, privacy, and cost. From MediaPipe, TensorFlow Lite, Core ML, and ONNX Runtime to OpenAI, Claude, and Gemini, I choose the right approach for your product instead of forcing one technology everywhere. Building a shared codebase is the easy part. Building one where iOS feels just as native as Android is where experience matters. I specialize in Kotlin Multiplatform architectures that share business logic while integrating cleanly with native platform APIs, so your team can ship features faster without compromising either platform. A great fit if you're building a new mobile product, modernizing separate iOS and Android apps, or developing a real-time platform such as ride hailing, delivery, logistics, or another location-based service. What I build - Ride hailing & taxi booking apps - Food delivery & courier platforms - Logistics & fleet management apps - Real-time GPS tracking & live location - Maps, routing & ETA calculation - Driver, customer & admin applications - Push notifications, chat & real-time updates - Payment gateway & wallet integration - AI assistants & smart search - On-device AI & cloud LLM integration - Kotlin Multiplatform architecture for iOS & Android AI Capabilities: RAG pipelines - context-aware retrieval over private knowledge bases, with hybrid local/cloud embeddings On-device LLMs - quantized models via MediaPipe, TF Lite, Core ML, ONNX Runtime LLM integration - OpenAI, Anthropic Claude, Gemini, plus self-hosted LLaMA and Mistral Vector search - Pinecone, Weaviate, ChromaDB, and on-device alternatives AI agents - function-calling, tool use, memory, multi-step reasoning Fine-tuning & prompt engineering for domain-specific tasks Mobile foundation Native Android (Kotlin, Java, Jetpack Compose) and iOS, plus Kotlin Multiplatform (KMP/KMM), Compose Multiplatform, and Flutter. Backend in Spring Boot when AI features need server support. Architecture: Clean Architecture, MVVM/MVI, modularization, TDD. Code an enterprise team can take over without a rewrite. Domains I've shipped in - Ride Hailing/Taxi Booking - Blockchain & Web3 mobile apps - VoIP & real-time communication - Food Delivery - Ecommerce - Mobile security & anti-theft - AI-powered consumer and enterprise apps How to start Send me a paragraph about your project. Within 1 hour I'll reply with a realistic scope estimate, the architectural approach I'd take, and a flag for anything that looks harder than it sounds.

🟢 AVAILABLE NOW Hey there! My name is Kousik Das and I'm a professional mobile app developer with over 5 years of experience in building high-quality, cross-platform mobile apps for Android and iOS. I will follow your requirements and definitely offer you the best-designed, neat and excellent work with quality testing. I have solo-developed and published full-stack applications to the App Store, Play Store, and web with 5000+ daily active users. I can own every aspect of the development cycle and would love to bring your application to life! 📌 Expertise 🔹On-Demand Apps (Uber-style taxi, cargo transport) 🔹E-commerce & Lifestyle (shopping, fashion, food delivery, salon booking) 🔹Travel Apps 🔹Education & Learning (tutor–student marketplaces, quizzes, e-learning) 🔹Social Networking (messaging, dating, sharing) 🔹 Media & Streaming (video editing, live streaming, real-time apps) 📌 Technology Stack 🔹 Android development (Kotlin, Java) 🔹 iOS development (Swift/SwiftUI) 🔹 iOS + Android development (Flutter/Dart, React Native) 🔹 Website development (PHP/ReactJS/NextJS) 🔹 Database design(MSSQL Server, MySQL, MongoDB, Postgres) 🔹 API development(Java Spring Boot, Cake PHP, NodeJS) 🔹 Version control (GitHub, BitBucket, SVN) 🔹 Task Manager (Jira, Trello, Basecamp) 📌 Work Ethics 🔹 Correct time management 🔹 Experience in project management 🔹 High Scalability of your idea 🔹 Quality of the final product 🔹 Fulfilment of actual need and maintain long-term client relationship 🔹 Customer time-to-value after delivery 🔹 6 months support after product live Feel free to contact me anytime! Thank you for going through my profile.

AI-Powered Mobile Engineer • Flutter & Native iOS/Android expert • Full-stack development with Node.js, Python, PHP & Firebase • Scalable backend systems on AWS & Kubernetes What I Build • Mobile apps (Flutter & Native) • SaaS platforms & MVPs • AI-powered applications & chatbots • Cloud-native scalable architectures Integrations & Technologies Flutter • Swift • Kotlin • Node.js • Python • Firebase • AWS • Kubernetes • MongoDB • PostgreSQL • REST APIs • AppsFlyer • Firebase Analytics • Payment & Chat SDKs What You Can Expect • Clean, scalable, production-ready systems • Fast execution with strong architecture decisions • Proactive communication & regular updates • Reliable long-term technical partnership Share your product idea, bottleneck, or existing app challenges, I’ll help with a structured roadmap, technical direction, and execution plan. ---------------------------------------------------------- Experience Across Industries • Healthcare & Fitness • FinTech & eCommerce • Ride-Hailing & Food Delivery • Dating & Matrimonial • Education & Gaming • IoT & BLE Applications

I’m a Computer Engineering graduate and Mobile Developer with over 15+ years of experience building high-quality mobile applications for iOS and Android using both native and cross-platform technologies. I specialize in native iOS and Android development (Swift / Objective-C, Kotlin / Java) as well as cross-platform frameworks such as Flutter (Dart) and React Native (JavaScript). In addition to mobile development, I also integrate Artificial Intelligence into my workflow and solutions. By leveraging modern AI tools and AI-powered development processes, I’m able to significantly reduce development time while maintaining high code quality and scalability. This allows me to deliver solutions faster and more efficiently for clients. I also have strong experience designing and integrating RESTful APIs using .NET, working with AWS cloud services, and building applications that incorporate AI capabilities such as Voice AI, speech-to-text, and AI-powered video features. Skills & Experience AI & Automation • Voice AI integrations • Speech-to-Text systems • AI video generation and processing • AI-assisted development workflows to accelerate delivery Cloud & Infrastructure • AWS (API hosting, storage, integrations) Backend & APIs • .NET APIs • Firebase (Authentication, Realtime Database, Storage, Analytics, Push Notifications) • Google APIs (Maps, Places) • AdMob integrations Payments & Subscriptions • Stripe • PayPal • RevenueCat (In-App Purchases, subscriptions, entitlements) iOS Development • Swift / Objective-C • UIKit, SwiftUI • CoreLocation, CoreBluetooth • AVFoundation • Push Notifications • In-App Purchases • Background Tasks • Local Storage Android Development • Kotlin / Java • Location & Sensors • Services, Camera, External Storage • Fragments, Content Providers, Broadcast Receivers • Unit Testing, WebView, SQLite • Custom Views, ConstraintLayout, Material Design Libraries & Tools • Retrofit • Realm • Glide / Picasso • OneSignal • Estimote Proximity SDK I focus on delivering scalable, high-quality solutions with clean architecture, efficient development processes, and clear communication. My goal is always to help clients launch faster, reduce development costs, and build reliable applications that scale.

🚀 Senior Android Engineer | Kotlin & Kotlin Multiplatform Expert | 8+ Years Experience Passionate Android Engineer with 8+ years of hands-on experience building high-performance, scalable mobile applications used by thousands of users worldwide. I specialize in clean architecture, performance optimization, and modern Android development using Kotlin and Java. I also deliver cross-platform solutions using Kotlin Multiplatform (KMP), enabling shared business logic across Android and iOS while maintaining native performance and flexibility. 🔧 Core Expertise ✅ Native Android Development (Kotlin & Java) ✅ Clean Architecture, MVVM & Modular Codebases ✅ Jetpack Libraries (Compose, Navigation, Room, WorkManager) ✅ REST API Integration (Retrofit, Ktor, WebSockets) ✅ Payment Gateway Integration (Stripe, PayPal, Google Pay, In-App Billing) ✅ Firebase (Authentication, Firestore, FCM, Crashlytics, Analytics) ✅ Google Play Console – Deployment, Optimization & App Updates ✅ Responsive & Adaptive UI for Phones & Tablets ✅ Offline-First Apps with Room & Local Caching ✅ Push Notifications & Real-Time Updates ✅ Google Maps, Location Services & Third-Party SDK Integration ✅ Ad Network Integration (AdMob & mediation setup) ✅ Kotlin Multiplatform (Shared business logic for Android & iOS) ✅ KMP Libraries – Coroutines, Ktor, SQLDelight, Koin, Serialization 💡 Why Work With Me? I focus on writing clean, modular, and testable code that ensures long-term maintainability, smooth performance, and low crash rates. Whether you need: • A new Android app from scratch • Feature additions • Bug fixes • Performance optimization • Migration from Java to Kotlin • Or a cross-platform solution using KMP I help you ship production-ready mobile products — faster and smarter. Let’s build something powerful. 📱🚀

🏆 Top Rated | 100% Job Success | 5/5 Client Ratings | 15+ live apps shipped 🏆 💡 I build mobile apps with AI baked in not bolted on. Hi, I'm an Android & iOS Mobile App Developer and AI Integration Expert, helping founders and established teams ship production-quality mobile products with real AI features users actually use. 🚀 Android & iOS Mobile App Developer | AI Integration Expert | Swift • Kotlin • React Native • Flutter As a Top Rated Android & iOS mobile app developer on Upwork with a 100% Job Success Score and 15+ live apps shipped, I help clients go from a rough idea to a scalable, AI-powered mobile product on the App Store and Google Play. Whether you need a native iOS app with Swift, a native Android app with Kotlin, or a cross-platform solution, I deliver Android & iOS mobile app development with AI integration OpenAI GPT-4, Google Gemini, LangChain, and RAG pipelines built in from day one. From health & wellness and fintech to e-commerce and SaaS, my experience as an AI-integrated mobile app developer spans multiple industries backed by a production team that has shipped 50+ live products, so you're never bottlenecked by a single point of failure. ✅ Why Partner with Me as Your Android & iOS Mobile App Developer: 15+ successful iOS and Android apps, live on the App Store and Google Play AI integration expertise OpenAI GPT-4, Google Gemini, LangChain, RAG pipelines, vector databases 100% Job Success Score and Top Rated status on Upwork Backed by a full production team for scalability beyond a single freelancer Cross-platform builds (Flutter, React Native) and native builds (Swift, Kotlin) AI-powered mobile apps chatbots, smart assistants, predictive features, semantic search Fintech, Health & Wellness, E-commerce, and SaaS mobile app development MVP App Development from idea to App Store & Google Play launch AI Mobile App Development: retrofitting AI into existing products users already love 🛠️ Services I Provide as an Android & iOS Mobile App Developer (AI Integration): Native iOS app development with Swift & SwiftUI Native Android app development with Kotlin & Jetpack Compose Cross-platform app development with React Native & Flutter AI integration: OpenAI GPT-4, Gemini, LangChain, RAG pipelines, vector databases UI/UX design for iOS and Android apps Backend & cloud integrations: Firebase, Supabase, AWS REST and GraphQL API development CI/CD and App Store / Google Play submission 🎯 Industries I Specialize In as an Android & iOS Mobile App Developer: 💊 Health & Wellness | 💰 Fintech | 🛒 E-Commerce | 📊 SaaS Platforms | 🤖 AI-Powered Apps All powered by Android & iOS mobile app development with AI integration built in. 🚀 Advanced Features I Build with AI Integration: ✔ AI chatbots & smart assistants (OpenAI, Gemini) ✔ RAG pipelines with vector databases for context-aware AI ✔ Predictive features & personalization engines ✔ Firebase & cloud-based backend integrations ✔ Real-time chat & push notifications ✔ Social login (Google, Apple) ✔ Offline mode & smart data sync ✔ App Store Optimization & submission 💬 Why Choose Me as Your Android & iOS Mobile App Developer: I bring deep expertise in Android & iOS mobile app development with AI integration built in from day one not retrofitted as an afterthought. Whether you're a startup building an MVP or an established team modernizing your product with AI, I'm the Android & iOS mobile app developer and AI integration expert who can turn your vision into a shipped, scalable product. 📲 Let's connect and build a powerful AI-integrated mobile app together. Your trusted Android & iOS mobile app developer and AI integration expert is just one click away. Send over your brief or even a rough idea I'll respond with questions, a realistic timeline, and an honest take on fit. Mobile App Development, iOS Development, Android Development, Flutter, React Native, Swift, Kotlin, Firebase, OpenAI API, ChatGPT Integration, Gemini AI, AI Mobile Apps, Cross-Platform App Development, API Integration, UI/UX Design, Native Mobile Apps, SaaS Apps, E-commerce App Development, RAG, LangChain, Vector Database

With 5+ years of experience and a 100% Job Success score, I’ve contributed to Android apps that reached 1+ million downloads with a 4.7 rating. I build production-ready mobile applications for e-learning, AI, e-commerce, health tech, and IoT industries. I specialize in native Android development (Kotlin, Java, Jetpack Compose) and cross-platform apps using Kotlin Multiplatform (KMP), applying Clean Architecture, Coroutines & Flows, and solid unit/UI testing to keep codebases scalable and maintainable. From custom UI and animations to complex integrations like Firebase, REST APIs, Google Maps SDK, and Stripe payments, I handle the full mobile app lifecycle from idea and MVP to Play Store launch and ongoing improvements. Core technologies: Kotlin, Java, Jetpack Compose, Kotlin Multiplatform (KMP), Clean Architecture, Coroutines & Flows, Unit/UI Testing, System APIs, Databases, Custom UI, Animations, Firebase, REST APIs, Google Maps SDK, Stripe SDK, Git, CI/CD